Flexible circuits are often used for interconnection of electrical signals between various miniature electrical components. A flexible circuit is generally composed of a collection of flexible electrically conductive traces formed on a flexible electrically insulating support structure or substrate. When used as testing or probing circuits, the flexible circuit further includes a plurality of small probes generally mechanically attached to the traces of the flexible printed circuit. The probes electrically contact a second electrical circuit, for example an integrated circuit (IC) wafer or the like, by touching contact or bond pads formed thereon. Signals are then read by the flexible circuit to determine the integrity of the circuit formed on the IC wafer.
Currently, low cost testing procedures and technologies are being sought to accommodate a recent demand for producing smaller, more complex and less costly electrical circuits. The probes formed on the flexible circuit, which are consequently reduced in size to accommodate the smaller pitch between bond pads, cannot easily be fixed to the flexible circuit in proper position and orientation using conventional welding or soldering techniques.
Thus, it is an object of the present invention to provide a flexible circuit including micro-sized probe tips that make effective electrical connections with smaller, more complex electrical circuits. It is a further object of the present invention to provide a method of fabricating a flexible circuit including micro-sized probe tips that meet the testing requirements of the smaller and more complex circuits where the fabrication method is economically feasible.